FIG. 1 shows the cross-section of a major portion of a conventional hybrid integrated circuit assembly. Various components (not shown) constituting a hybrid integrated circuit are packaged on a substrate 1. A heat sink 2 dissipates heat generated by the components on the substrate 1. The heat sink 2 comprises a land 21 to which the substrate 1 is bonded, portions or feet 22 to be soldered to a board on which the hybrid integrated circuit assembly is to be mounted, and legs 23. The heat sink 2 is bonded to the substrate 1 by a bonding agent 3. There are further provided a plurality of terminals 4 which are spaced in a direction perpendicular to the plane of the sheet of FIG. 1. Each of the terminals 4 comprises a distal portion 41 connected to the substrate 1, a proximal portion 42 soldered to the board 9, and an interconnecting portion 43 connecting the portions 41 and 42.
This hybrid integrated circuit assembly is fabricated by first packaging circuit components on the substrate 1, connecting the terminals 4 to the substrate, and after that, bonding the heat sink 2 to the substrate by means of the bonding agent 3. For connecting the terminals 4 to the substrate 1, a comb-shaped terminal member including a number of terminals 4 having respective base or outer ends of the proximal portions 42 connected to a lead body is used. After desired terminals 4 are connected to the substrate 1, the terminals 4 are separated from the lead body. Such a technique is described in, for example, Japanese Unexamined Utility Model Publication No. SHO 60-54341 published or laid open to public on Apr. 16, 1985.
The hybrid integrated circuit assembly shown in FIG. 1 is used with the heat sink feet 22 and the terminal proximal portions 42 soldered to the board 9. In this case, the surfaces of the feet 22 and the surface of each of the proximal portions 42 must be in the same plane. If they are not in the same plane, some areas will be detached from the board surface so that they cannot be soldered well to the board 9, resulting in inadequate connection. Conventionally, the terminals 4 are individually fabricated or fabricated in the form of a terminal member, and the heat sinks 2 are fabricated as individual members. That is, the terminals 4 and the heat sink 2 are fabricated separately. Therefore it occurs very frequently that the surfaces of the feet 22 of the heat sink 2 and the proximal portions 42 of the terminals 4 which are to be bonded to the board 9 are not in the same plane, due to dimensional errors of the respective parts, to which an assembling error is further added. In addition, if the substrate is warped, the warpage adds to the difference between the planes of the mounting surfaces of the portions 22 and 42, which results in inadequate connections to the board 9.
An object of the present invention is to provide a hybrid integrated circuit assembly free of the above-described disadvantage of the conventional assembly, by providing an integral heat sink-terminal member structure which is free of any difference in the planes of the surfaces of a heat sink and terminals which are soldered to a board.
Another object of the present invention is to provide a method of using such a structure or a method of manufacturing a hybrid integrated circuit assembly using such an integral heat sink-terminal member structure. According to this method, a resulting hybrid integrated circuit assembly is free of disconnection of the heat sink or terminals and the board.